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SpaceX sticks the landing perfectly!

I was watching the webcast live last night, but they didn't show this view from a helicopter at the Cape:

Sorta bummed that they didn't try for the barge again, since they were stationing it right off the coast near where I'm spending the holidays. Still, impressive accomplishment for what is essentially a startup company with no long history of spaceflight through military contracts and stuff. (It was overcast here anyway.)

A news story on the local radio here this morning said that Musk wasn't sure if they would try to re-fly this booster or keep it around because it was the first to land successfully, but his engineers will have plenty of time to study it.....

I wonder how much altitude and delta-V (and thus payload to orbit) they're giving up but doing stage separation early enough to retain sufficient fuel -- not so much for landing the first stage, the fuel needed to do that is apparently fairly minimal, but by turning it around (from a 6000 km/h velocity!) and bringing it back to the launch site. The original scheme of landing it on a barge positioned well down-range made far more sense to me from that perspective.

-Uwe-

Last edited by Uwe; 12-22-2015 at 11:17 AM.

The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

I wonder how much altitude and delta-V (and thus payload to orbit) they're giving up but doing stage separation early enough to retain sufficient fuel -- not so much for landing the first stage, the fuel needed to do that is apparently fairly minimal, but by turning it around (from a 6000 km/h velocity!) and bringing it back to the launch site. The original scheme of landing it on a barge positioned well down-range made far more sense to me from that perspective.

They've done some upgrades for this launch (like deep cryo propellants) and they're getting some more performance from both stages, and stage 2 in particular was stretched a bit. I think they stage a bit earlier as a result.

My understanding is this: Before the upgrades, they were in a position to land downrange on the barge for some missions, but others they had to fly expendable because they needed every bit of performance to hit their customer's requirement. After the upgrades, all of their currently contracted missions have enough margin for stage 1 recovery, usually back to land, or downrange on the barge if they must. Anything in the future that would need all of Falcon 9 v1.2's performance in expendable mode will instead be flown cheaper using Falcon Heavy in recoverable mode. Falcon Heavy side cores will RTLS as they separate pretty early but the center core will almost certainly need the barge due to downrange distance and speed.

Turning the first stage around sans the mass of the second stage and all of the first stage fuel that was burned off on ascent probably isn't too difficult. During the live stream, they said that only three (of the 9?) engines were used on the first burn, and there was a lot of unpowered descent with the steering flaps guiding it towards LZ-1. This is the first flight of the new booster, and it was enlarged to provide enough fuel for a comfortable first stage RTLS. My impression is that the FAA would not give them permission to RTLS until they demonstrated the ability to control the booster, which was the whole purpose of the water landings and then two [long] shots at the barge. This was the first flight after the FAA signed off on RTLS, and obviously everything worked to perfection.....